import sys
input = sys.stdin.readline

def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))

def main():
    mod=10**9+7
    X=I()
    if X>=30:
        print("Yes")
    else:
        print("No")

main() import sys sys input = sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline def I(): return int(input()) I def MI(): return map(int, input().split()) MI def LI(): return list(map(int, input().split())) LI def main():
    mod=10**9+7
    X=I()
    if X>=30:
        print("Yes")
    else:
        print("No") main mod=10**9+7 mod 10**9+7 10**9 10 9 7 X=I() X I() I if X>=30:
        print("Yes")
    else:
        print("No") X>=30 X 30 print("Yes") print "Yes" print("No") print "No" main() main input = sys.stdin.readline sys.stdin.readline input def LI(): return list(map(int, input().split())) def LI(): return list(map(int, input().split())) LI def MI(): return map(int, input().split()) def MI(): return map(int, input().split()) MI def I(): return int(input()) def I(): return int(input()) I def main():
    mod=10**9+7
    X=I()
    if X>=30:
        print("Yes")
    else:
        print("No") def main():
    mod=10**9+7
    X=I()
    if X>=30:
        print("Yes")
    else:
        print("No") main
import sys
input = sys.stdin.readline

def I(): return int(input())
def MI(): return map(int, input().split())
def LI(): return list(map(int, input().split()))

def main():
    mod=10**9+7
    X=I()
    if X>=30:
        print("Yes")
    else:
        print("No")

main()
